The present invention relates to a glass panel for improving heat insulating performance. The invention relates, more particularly, to a glass panel formed by assembling together a plurality of glass sheets with a plurality of spacers being interposed therebetween for forming a space and with outer peripheral edges of the plurality of glass sheets being sealed, and a method of manufacturing such glass panel, and relates further to the spacer for use in such glass panel.
Conventionally, such glass panel, as shown in FIGS. 48 and 49 for instance, is manufactured by disposing a plurality of spacers 5 made of cylindrical glass prepared in the form of spacers at predetermined positions on a spacer-disposing face 2A of a first glass sheet 1A, superposing a second glass sheet 1B thereon, and sealing outer peripheral edges 3 of the two glass sheets with a sealing material S made of low-melting glass.
Also, with the above-described glass panel, the inside of the space 4 is maintained under a pressure-reduced condition, in order to enhance the heat insulating performance and sound insulating performance. For this reason, the great number of spacers 5 are interposed between the first glass sheet 1A and the second glass sheet 1B so as to allow the atmospheric pressure acting on the outer surface of the first glass sheet 1A or second glass sheet 1B to be substantially uniformly born by the entire glass sheets, whereby breakage or cracking of the first glass sheet 1A and second glass sheet 1B may be avoided.
For manufacturing a glass panel, generally, after the spacers 5 are disposed on the surface of the first glass sheet 1A, the second glass sheet 1B is superposed thereon. With the conventional glass panel, the disposing operation of the spacers 5 at predetermined positions on the first glass sheet 1A is done by a worker""s manual operation of disposing the spacers 5 one by one on the first glass sheet 1A or by using a suction-conveying device operable to suck the plurality of spacers (5) to be disposed within a predetermined area at one time and then to place them on the first glass sheet 1A.
Further, with the above-described conventional art, a great number of spacers 5 need to be manufactured in advance and these spacers 5 need to be placed with a predetermined distance therebetween on the sheet face of the first glass sheet 1A. Moreover, a separate operation is needed for bonding these spacers 5 on the first glass sheet so as to prevent movement of the spacers. Hence, the handling of the spacers 5 would be troublesome and the manufacturing process of the glass panel would be complicated.
For example, with the conventional glass panel manufacturing method described above, the mere disposing operation of the spacers 5 on the first glass sheet 1A cannot prevent inadvertent displacement or tumbling of the spacers 5 in the course of the superposing operation of the second glass sheet 1B unless the spacers 5 are fixed in advance. Therefore, the superposing operation of the two glass sheets 1A, 1B is troublesome, hence, the productivity is poor. Then, it is conceivable to bond the spacers 5 on the first glass sheet 1A However, it is not easy to bond such great number of small objects.
In view of the above, as shown in FIGS. 42 through 44 for example, the convention has proposed an alternative method (e.g. the European patent Serial No. 0047725), in which case spacer-forming paste 11 which is prepared by mixing together low-melting glass frit and caking additive is caused to adhere, in the form of paste-formed members 10 having predetermined dimensions, to the respective predetermined positions on the two glass sheets 1A, 1B (see FIG. 42), then after placing the leading ends of these paste-formed members 10 into abutment with each other, the members are baked (see FIG. 43), so as to be combined together into the spacers 5, and also these spacers 5 are bonded to the respective glass sheets 1A, 1B (see FIG. 44).
However, in order to realize this proposal, it is necessary to arrange the small paste-formed members 10 with high precision on the faces 2 of the opposed glass sheets 1A, 1B on the side of the space 4. That is, as shown in FIG. 45 for instance, if there occurs error in the relative positioning between the two glass sheets 1A, 1B, this will result in misalignment as shown in FIG. 46 between the opposed paste-formed members 10. As a result, there will be formed some misaligned spacers 5 at mid-positions as shown in FIG. 47. With such misalignment, there is the risk of the spacers 5, when used, being broken at such misaligned positions. Moreover, if there is extreme misalignment between the opposed paste-formed members 10, the spacers 5 bonded to the opposed glass sheets 1 will not be bonded with each other, so that they will fail to function properly as spacers 5. Therefore, very careful positioning operation is needed. Hence, when the two glass sheets 1A, 1B are assembled together, a precise positioning operation is needed and the operation is not easy.
Also, the two glass sheets 1A, 1B after being assembled together are completely restricted in position relative to each other by means of the spacers 5. Then, if there occurs deformation of the glass panel, such as warping thereof, due to an external force, e.g. wind pressure, acting on the glass panel, this will cause mutual displacement between the two glass sheets 1A, 1B, so that the spacers 5 may be broken or the glass sheets 1 may be damaged.
Moreover, of the conventional methods described above, in the case of the worker""s manual operation of disposing all of the spacers 5 on the first glass sheet 1A, this operation is very troublesome and the production efficiency of the glass panel is low.
On the other hand, in the case of disposing the spacers 5 by using the suction-conveying apparatus or the like, such suction-conveying apparatus needs to be prepared separately. Moreover, a plurality of such suction-conveying apparatuses need to be prepared in order to cope with all possible sizes of glass sheets. Hence, there occur such inconveniences as disadvantageous diversification of the required manufacturing system, necessity of maintenance of the system, which all lead to increase in the required costs. Further, in this case, some of the spacers 5 disposed on the first glass sheet 1A may not be disposed properly, with improper inclined or lateral orientation. Thus, there was a limit in possible improvement of the efficiency of disposing operation of the spacers 5.
The present invention has been made in view of the above-described state of the art and its object is to provide a glass panel which is easy to manufacture and has superior productivity and which can prevent damage of the glass sheets and a method of manufacturing such glass panel and also to provide spacers for use in such glass panel.
The characterizing features of the glass panel according to the present invention are as follows.
A glass panel relating to claim 1, as shown mainly in FIG. 9, comprises a pair of first and second glass sheets disposed with sheet faces thereof opposed to each other, a plurality of spacers interposed between the pair of glass sheets for forming a space therebetween, and a sealing glass for bonding peripheral edges of the glass sheets together for sealing the space, the sealing glass having a fusing temperature lower than a softening point of the glass sheets, wherein each spacer is formed by disposing spacer-forming paste in a predetermined shape on the sheet face of the glass sheet and then baking the paste, said spacer-forming paste containing glass component which has a fusing temperature lower than the softening point of the glass sheets and a softening point higher than a fusing temperature of the sealing glass.
That is to say, the spacer fused to glass sheets may be formed by disposing the spacer-forming paste containing a glass component having a lower fusing temperature than the softening point of the glass sheets in a predetermined shape on the sheet face of the glass sheet and then baking this paste. Thus, there is no necessity of manufacturing a great number of spacers in advance, and the spacers may be easily bonded and fixed in position with a predetermined distance therebetween on the sheet face of the glass sheets.
Also, since the glass component contained in the paste has a softening point higher than the fusing temperature of the sealing glass, there is no risk of the spacers being softened and deformed when the sealing glass is heated for bonding together the peripheral edges of the two glass sheets.
Accordingly, there is no necessity of manufacturing a great number of spacers in advance, and there is no necessity, either, of disposing these spacers on the sheet face of the glass sheet with a predetermined distance. In addition, the separate bonding operation for bonding these spacers to the glass sheets is not needed, either. As a result, handling of the spacers is easy and the glass panel may be manufactured easily.
Further, as there is no risk of the spacers being softened and deformed in the course of bonding operation of the peripheral edges of the two glass sheets together with the sealing glass, the distance between the two glass sheets may be maintained properly, so that a desired heat-insulating performance may be readily assured.
A glass panel relating to claim 2, as shown in FIGS. 1-5, is characterized in that the spacer is formed by baking the paste which is disposed on the sheet face of the first glass sheet alone.
That is to say, as the space between the two glass sheets is formed by disposing the spacer which is fused only to the first glass sheet, relative displacement between the spacer and the second glass sheet may be allowed even if the glass panel is deformed by warping.
Accordingly, even when the glass panel is warped, there is less risk of this glass panel being broken.
A glass panel relating to claim 3 is characterized in that the glass component contained in the paste has a lower lead content and a higher silicon content than the sealing glass.
Accordingly, it is easy to set the softening point of the spacer to a higher temperature than the fusing temperature of the sealing glass.
A method of manufacturing a glass panel relating to claim 4 comprises the steps of: preparing spacer-forming paste capable of forming spacers; forming and disposing the spacer-forming paste in a predetermined shape on the space-side face, i.e. spacer-disposing face, of a first glass sheet; subsequently effecting a predetermined solidifying operation on each spacer-forming paste so as to form a plurality of pre-spacer forming elements; effecting a height-adjusting shaping operation on respective contacting ends capable of contacting a second glass sheet of the plurality of solidified pre-spacer forming elements into a predetermined height relative to the spacer-disposing face; and assembling the second glass sheet with the first glass sheet with a space-side face of the second glass sheet being opposed to the height-adjusted shaped contacting ends.
With this method, the manufacture of the glass panel may be facilitated and also the damage of the glass panel may be avoided. That is, because the spacer-forming paste is disposed on the spacer-disposing face, i.e. the space-side face, of the first glass sheet, the assembling operation of the two glass sheets does not require precise mutual positioning. This is because the spacers may only be distributed properly on the spacer-disposing face. Further, the spacer-forming paste is subjected to the predetermined solidifying operation (e.g. a baking operation in case e.g. a low-melting glass paste is employed) to be formed into the spacers. Then, if each of these spacers is subjected to the height-adjusting shaping operation (e.g. in case the above-described paste is employed, the contacting ends of the pre-spacer forming elements after the baking operation thereof will be heated again and pressed at the softening temperature) to obtain a predetermined height relative to the spacer-disposing face, when the second glass sheet is assembled by sealing the outer peripheral edges, there will occur no such trouble of only a limited number of the spacers coming into contact with the second glass sheet. As a result, there may be obtained a glass panel having a stable construction. Moreover, as the spacers are not bonded to the space-side face of the second glass sheet, relative movement is allowed between the spacers and the second glass sheet. Accordingly, deformation, e.g. warping, of the glass panel may be effectively absorbed through the mutual displacement between the spacers and the second glass sheet.
A glass panel manufacturing method relating to claim 5, as shown in FIG. 8 for instance, is characterized in that the height-adjusted, shaped contacting end of the spacer in claim 4 is then subjected to a grinding operation to form convex and concave portions at this contacting end.
With this method, in addition to the effect achieved by the method of claim 4, the heat-transfer resistance between the spacer and the second glass sheet may be enhanced, thereby to restrict heat conduction via the spacer. As a result, stress concentration may be avoided for effectively preventing development of cracks in the glass sheet.
That is to say, as shown in FIG. 8, as the contact portions in the form of convex portions are formed in the contacting end of the spacer, the contact area of the contact portions relative to the second glass sheet may be reduced. Moreover, since substantially entire area of the contacting end including the concave portions of the contacting end of the spacer functions as the contact area for contacting the second glass sheet, it becomes possible to avoid stress concentration to the second glass sheet. Further, with such reduced contact area, it becomes also possible to increase the heat-transfer resistance between the second glass sheet and the spacer.
A method of manufacturing a glass panel relating to claim 6, as illustrated in FIGS. 1 through 7, comprises the steps of: preparing spacer-forming paste capable of forming spacers; forming and disposing the spacer-forming paste in a predetermined shape on the space-side face, i.e. spacer-disposing face, of a first glass sheet (see FIG. 3); subsequently effecting a predetermined semi-solidifying operation on each spacer-forming paste so as to form a plurality of semi-solidified pre-spacer forming elements (see FIG. 4); effecting a height-adjusting shaping operation on respective contacting ends capable of contacting a second glass sheet of the plurality of pre-spacer forming elements into a predetermined height relative to the spacer-disposing face (see FIG. 5); subjecting each said height-adjusted pre-spacer forming element to a predetermined solidifying operation to form it into a spacer; and assembling the second glass sheet with the first glass sheet 1A (see FIG. 7) with a space-side face of the second glass sheet being opposed to the height-adjusted shaped contacting ends (see FIG. 6).
With this method, the manufacture of the glass panel may be facilitated and also the damage of the glass panel may be avoided. That is, as illustrated in FIGS. 1 through 7, because the spacer-forming paste is disposed on the spacer-disposing face, i.e. the space-side face, of the first glass sheet, the assembling operation of the two glass sheets does not require precise mutual positioning. This is because the spacers may only be distributed properly on the spacer-disposing face. Further, the spacer-forming paste is subjected to the predetermined semi-solidifying operation (e.g. in case a low-melting glass paste is employed, the paste is baked and then is maintained at a temperature higher than the softening point so as to maintain its semi-solidified state) to be formed into the semi-solidified pre-spacer forming elements. Then, if each of these is subjected to the height-adjusting shaping operation (the pre-spacer forming element is pressed, under a temperature condition in which the element is slightly softened, by the space-side face of the second glass sheet, so as to form it simultaneously with the assembly operation thereof to the first glass sheet and the sealing operation of the outer peripheral edges) to obtain a predetermined height relative to the spacer-disposing face, when the second glass sheet is assembled by sealing the outer peripheral edges, there will occur no such trouble of only a limited number of the contacting ends coming into contact with the second glass sheet. As a result, there may be obtained a glass panel having a stable construction.
Moreover, as the spacers are not bonded to the space-side face of the second glass sheet, the contacting end of the spacer and the space-side face of the second glass sheet are free from each other, so that relative movement is allowed between the spacers and the second glass sheet. Accordingly, deformation, e.g. warping, of the glass panel may be effectively absorbed through the mutual displacement between the spacers and the second glass sheet.
A glass panel manufacturing method relating to claim 7, as illustrated in FIGS. 1 through 5 for instance, is characterized in that the spacer-forming paste is mixed by adding a binder to the low-melting glass having a lower fusing temperature than the softening point of the glass sheet in any one of claims 4 through 6; this spacer-forming paste is baked under a predetermined baling temperature together with the first glass sheet to be formed into the plurality of pre-space forming elements; and the contacting ends are height-adjusted by pressing while these pre-spacer forming elements are maintained at the softening temperature of the pre-spacer forming elements which is lower than the baking temperature.
In this regard, the fusing temperature of the low-melting glass refers to such a temperature as the viscosity of the low-melting glass becomes fluidized, e.g. the viscosity becomes below 105 poise.
With this method, in addition to the effects achieved by the methods of claims 4-6, there is obtained a further effect that the spacer may be formed into the predetermined shape while this spacer is fused to the second glass sheet.
That is to say, as shown in FIGS. 1 through 5, for forming the spacers, the pre-spacer forming elements fused to the second glass sheet may be formed by baking the spacer-forming paste comprising the low-melting glass having a fusing temperature lower than the softening point of the glass sheets. Therefore, it is possible then to effect the height-adjusting shaping operation of the spacer by pressing the pre-spacer forming element while it is maintained at its softening temperature which is lower than the baking temperature.
A glass panel manufacturing method relating to claim 8, as illustrated in FIG. 10 for instance, is characterized in that the spacer-forming paste is prepared by adding to the low-melting glass particles of convex forming elements having a heat-resistant temperature higher than the softening temperature of the pre-spacer forming elements in claim 7 and them together.
With this method, in addition to the effect achieved by the method of claim 7, it becomes also possible to form the convex portions in the contacting end of the spacer without any particular working.
That is, as illustrated in FIG. 10, since the convex forming element has a higher softening point than the fusing temperature of the pre-spacer forming element comprised of the low-melting glass constituting the spacer-forming paste, the particles of the convex forming elements can form convex portions on the surface of the contacting end of the spacer, when the low-melting glass is solidified.
A glass panel manufacturing method relating to claim 9, is characterized in that in the height-adjusting shaping step of the contacting end according to any one of claims 4-7, the contacting end is shaped into a flat smooth face as shown in FIGS. 1 through 5 for instance.
With this method, in addition to the effects achieved by the methods of claims 4-7, there is obtained still further effect that damage of the spacers and glass sheetes may be prevented.
That is to say, as shown in FIGS. 1 through 5, as the contacting end of each spacer for contacting the second glass sheet is formed as a flat smooth face, the sliding resistance of the contacting end against the space-side face of the second glass sheet is reduced, so that they may readily slide against each other in the case of deformation of the glass panel. As a result, the external force affecting the spacer during deformation of the glass panel may be reduced advantageously.
Moreover, the height-adjusting shaping operation of the pre-spacer forming element may be carried out simply by pressing it into a flat surface. Therefore, this shaping operation may be very easy.
A glass panel manufacturing method relating to claim 10, as shown in FIGS. 2 and 7 for instance, comprises the steps of: preparing spacer-forming paste capable of forming spacers; forming and disposing the spacer-forming paste in a predetermined shape and at a plurality of predetermined positions on the space-side face, i.e. spacer-disposing face, of a first glass sheet; effecting a height-adjusting shaping operation (e.g. by means of press-rolling using a roller (not shown)) on respective contacting ends capable of contacting a second glass sheet into a predetermined height relative to the spacer-disposing face; subsequently effecting a predetermined solidifying operation on each spacer-forming paste so as to form a plurality of spacers; and assembling the second glass sheet with the first glass sheet with a space-side face of the second glass sheet being opposed to the height-adjusted shaped contacting ends (see FIG. 7).
With this method, the manufacture of the glass panel may be facilitated and also the damage of the glass panel may be avoided.
That is, as illustrated in FIGS. 2 and 7, because the spacer-forming paste is disposed on the spacer-disposing face, i.e. the space-side face, of the first glass sheet, the assembling operation of the two glass sheets does not require precise mutual positioning. This is because the spacers may only be distributed properly on the spacer-disposing face.
Further, as the spacer-forming paste disposed on the spacer disposing face is formed into the predetermined shape while being height-adjusted so as to obtain a predetermined height relative to the spacer-disposing face (e.g. if the spacer-forming paste is height-adjusted by means of e.g. screen printing method in accordance with the thickness of the screen during the printing operation), then, when the spacers are formed by baking, there will occur no such inconvenience as only some of the contacting ends come into contact with the second glass sheet when the second glass sheet is assembled with sealing of the outer peripheral edges. As a result, there may be obtained a glass panel having a stable construction.
Moreover, as the spacers are not bonded to the space-side face of the second glass sheet, relative movement is allowed between the spacers and the second glass sheet. Accordingly, deformation, e.g. warping, of the glass panel may be effectively absorbed through the mutual displacement between the spacers and the second glass sheet.
A glass panel manufacturing method relating to claim 11, as illustrated in FIG. 8, is characterized in that in the height-adjusting shaping step of the contacting ends according to any one of claim 4, claims 6-8 and claim 10, convex and concave portions are formed in the contact end and the convex portions are shaped into the predetermined height.
With this method, in addition to the effects achieved by the methods of any one of claim 4, claims 6-8 and claim 10, there is achieved still further effect that the manufacturing process may be simplified while maintaining the required precision in the height of the contact portion.
That is to say, as illustrated in FIG. 8, the contacting end is ground to form the convex portions to form the convex portions in the original surface. Hence, the height-adjusting shaping operation may be carried out prior to the grinding operation. And, this height-adjusting shaping operation does not require press-shaping of both of the convex and concave portions, so that the shaping operation may be facilitated while the required height precision is maintained. As a result, the shaping operation of the contacting end may be facilitated.
A glass panel spacer relating to claim 12, as shown in FIG. 32, comprises a plurality of spacer bodies two-dimensionally interconnected to each other via a connecting member.
According to this construction, by interconnecting a plurality of spacer bodies in advance, these spacer bodies may be disposed at one time at the predetermined positions. So that, the disposing operation of the spacers may be carried out efficiently and consequently the production efficiency of the glass panel may be improved.
A glass panel spacer relating to claim 13 is characterized in that the connecting member may be shrunk or eliminated by means of heating.
If the connecting member is shrunk by means of heating as this construction, the connecting member may be less conspicuous when the glass panel is completed, whereby the transparency of the glass panel may be improved.
A glass panel spacer relating to claim 14 is characterized in that the connecting member may be dissolved by means of a solvent.
If the connecting member can be dissolved by means of a solvent, the connecting member may be removed entirely when the glass panel is completed, so that a glass panel having highest possible transparency may be obtained.